This invention relates to a coil winding machine capable of winding cylindrical coils to be used in electric apparatus such as transformers, induction coils, reactors, and the like.
Heretofore, a cylindrical coil as shown in FIGS. 1(A) and 1(B) of the accompanying drawing has been produced by winding an electrically conductive wire (hereinafter termed coil wire) b around an electrically insulating frame (hereinafter termed bobbin) a of a cylindrical configuration, by a required number of coil layers, and, during the coil winding operation, a corresponding number of interlayer insulating sheets c are inserted between the respective coil layers, simultaneous with the application of coil end insulators d.sub.1 and d.sub.2 onto both ends of the coil layers.
However, the thicknesses of the coil end insulating materials d.sub.1 and d.sub.2 are substantially equal to the diameter of the coil wire b which is far thicker than the thickness of the interlayer insulating sheet c, and therefore two kinds of insulating materials have been prepared for the production of such coils. Where it is necessary to prepare various kinds of insulating materials and it is desired to reduce the number of types of insulating material for the simplification of stock control or the like, an interlayer insulating sheet e as shown in FIG. 2 having two lateral sides e.sub.1 and e.sub.2 folded into a W shape may be has been used instead of a simple sheet of an insulating material.
Regardless of the types of the interlayer insulating sheets c or e, however, when it is used between the coil layers the length of each interlayer insulating sheet c must first be estimated, and the sheets c must be cut beforehand into the estimated lengths in a separate sheet cutter. During the coil winding operation, the interlayer insulating sheets c thus cut into the estimated lengths are inserted successively between the coil layers, and the longitudinal ends of the successive sheets must be joined together in an overlapping relation by an adhesive agent or the like.
For performing these processes, many of the conventional coil winding machines incorporate a sheet cutter cutting the interlayer insulating sheets into the respective lengths, a sheet supplying device supplying the interlayer insulating sheets into the required positions, and a sheet bonding device which joins the longitudinal ends of the interlayer insulating sheets during the coil winding operation, thus complicating the construction, and rendering the maintenance and handling of the machine extremely troublesome. Furthermore, the alternate executions of the coil layer winding steps and the insulating sheet insertion steps have reduced the operating speed of the coil winding machine, caused mass-production of the coils to be extremely difficult.